RE: The shape of the universe and what is at it's edge. Turn your noggins on.

(10-01-2012 04:18 PM)Chas Wrote: Sorry, I wasn't clear. All that we see is our universe. It was once infinitesimal, so the big bang 'happened everywhere' in our universe, not elsewhere.

The radiation that is there ISN'T the radiation we see now. The radiation we see now left there a billion years ago. When you look up in the sky, you are seeing the past on a vast scale.

I completely understand that. I'm saying that the radiation we are measuring may not be indicative of the current expansion/size of the universe but of how the universe was when the radiation was emitted. Is the possible age of the radiation we are measuring taken into consideration? Is the CBR we measure today a model of how the universe is now or how it was when the radiation was emittted?

I feel like I'm not explaining myself very well. When we view a star a million light years away we are seeing that star as it was a million years ago. So when we measure CBR a million light years away are we not seeing that radiation as it was a million years ago? And if we are, are we accurately depicting expansion as it really is today? Or a million years ago? Or 13.4 billion years ago?

edit. I've read your first sentence several times and it got me to thinking. I wonder how many people imagine the big bang as an explosion that happened in the center of a huge empty space (the space we see when we look up but with no stars in it) instead of understanding that the space we see today didn't exist at the time. That it grew outward in the 'explosion' of the BB.

“Whenever you find yourself on the side of the majority, it's time to pause and reflect.”

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

(10-01-2012 04:52 PM)germanyt Wrote:

(10-01-2012 04:18 PM)Chas Wrote: Sorry, I wasn't clear. All that we see is our universe. It was once infinitesimal, so the big bang 'happened everywhere' in our universe, not elsewhere.

The radiation that is there ISN'T the radiation we see now. The radiation we see now left there a billion years ago. When you look up in the sky, you are seeing the past on a vast scale.

I completely understand that. I'm saying that the radiation we are measuring may not be indicative of the current expansion/size of the universe but of how the universe was when the radiation was emitted. Is the possible age of the radiation we are measuring taken into consideration? Is the CBR we measure today a model of how the universe is now or how it was when the radiation was emittted?

We are seeing what was emitted then, long ago and far, far away.
We can't see what anything is doing now; in fact, 'now' is not a very useful concept at cosmic distances.

Quote:I feel like I'm not explaining myself very well. When we view a star a million light years away we are seeing that star as it was a million years ago. So when we measure CBR a million light years away are we not seeing that radiation as it was a million years ago? And if we are, are we accurately depicting expansion as it really is today? Or a million years ago? Or 13.4 billion years ago?

The cosmic background radiation is radiation that was produced 13.4 billion years ago and is just arriving here. We can't measure something a million light years away now - we can only see it as it was a million years ago.

Quote:edit. I've read your first sentence several times and it got me to thinking. I wonder how many people imagine the big bang as an explosion that happened in the center of a huge empty space (the space we see when we look up but with no stars in it) instead of understanding that the space we see today didn't exist at the time. That it grew outward in the 'explosion' of the BB.

I think that is a common misconception because the correct concept is so alien and outside of our common sense. Our brains evolved to deal with local space and time; going beyond that is a most wonderful aspect of our consciousness, along with philosophy, mathematics, ethics, etc.

Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

That is what I thought. So since everything we measure in regards to CBR is 13+ billion years old then how can we claim to understand the speed of the initial expansion or the current rate of expansion? I'm not trying to be difficult. I just can't recall reading anything about the redshift explaining current expansion or expansion as it was 13B years ago.

“Whenever you find yourself on the side of the majority, it's time to pause and reflect.”

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

I've been watching so many science documentaries lately, I'm not sure where I saw this. I think it was from the series, How The Universe Works. They showed this map of the universe created by recording background radiation with the WMAP.

Such a beautiful sight. I just wish there was a "You are here" tag so we could have a better idea of perspective.

Mind-blowing stuff indeed: What's "outside the bubble"? What is the universe expanding into?

It was just a fucking apple man, we're sorry okay? Please stop the madness
~Izel

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

(10-01-2012 05:26 PM)Erxomai Wrote: I've been watching so many science documentaries lately, I'm not sure where I saw this. I think it was from the series, How The Universe Works. They showed this map of the universe created by recording background radiation with the WMAP.

Such a beautiful site. I just wish there was a "You are here" tag so we could have a better idea of perspective.

Mind-blowing stuff indeed: What's "outside the bubble"? What is the universe expanding into?

The consistency of the radiation is key to explaining expansion. But what's confusing me is whether or not that is background radiation as it was 13 years ago or as it is today. If it is CMB as it was 13 years ago then how does it explain anything about the current state of the universe?

“Whenever you find yourself on the side of the majority, it's time to pause and reflect.”

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

(10-01-2012 05:29 PM)germanyt Wrote:

(10-01-2012 05:26 PM)Erxomai Wrote: I've been watching so many science documentaries lately, I'm not sure where I saw this. I think it was from the series, How The Universe Works. They showed this map of the universe created by recording background radiation with the WMAP.

Such a beautiful site. I just wish there was a "You are here" tag so we could have a better idea of perspective.

Mind-blowing stuff indeed: What's "outside the bubble"? What is the universe expanding into?

The consistency of the radiation is key to explaining expansion. But what's confusing me is whether or not that is background radiation as it was 13 years ago or as it is today. If it is CMB as it was 13 years ago then how does it explain anything about the current state of the universe?

In my naive understanding of the sciences, I believe since the universe is ever expanding, any "photo" is going to be obsolete as soon as it is taken. So, I'm guessing, no, it's not the same as the current state...unless perhaps the computer models are projecting a hypothetical current state? Wish I hadn't had my astronomy class at 7:30 in the morning during my senior year of college. I might have gone more often and maybe even cracked a book once in a while!

It was just a fucking apple man, we're sorry okay? Please stop the madness
~Izel

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

(10-01-2012 05:17 PM)germanyt Wrote: That is what I thought. So since everything we measure in regards to CBR is 13+ billion years old then how can we claim to understand the speed of the initial expansion or the current rate of expansion? I'm not trying to be difficult. I just can't recall reading anything about the redshift explaining current expansion or expansion as it was 13B years ago.

The most important fact about the cosmic background radiation is that it exists. Its existence is evidence of the Big Bang - without the CBR, the reality of a big bang would be doubtful. The fact that the radiation is from 13.4 billion years ago (as measured by red-shift) puts an age on the universe. It is in the microwave region of the spectrum because it is shifted so far to the red. The icing on the cake is the slight unevenness of it: it supports the chunkiness of the distribution of matter as galaxies, etc.

Skepticism is not a position; it is an approach to claims.
Science is not a subject, but a method.

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

Being insane is social licence if nothing else for standing outside... sounds like a question of such lack of meaning it is meaningful how much mathematical manufacture is invested in speaking out of our collective ass.

Shaping the universe is a divine commission most likely undertook in reaction to the action of witnessing Almighty God kicking it on our obscure backwater. Cause were "evil" like that. Every once in a while, we'll put down our legacy of self-entitlements, moral imperatives, hard-won reputations; and stop pointing. And for a moment, the whole network of me versus you shimmers like a spiderweb, recognized for what it is. Security blanket. Exchange in an instant the why of another, so that one day the one who was wronged can return. The need to be right when there's nothing left but blackened bones and refugee orphans; picking up, and putting down the trash. Becomes a point of I to ponder any direction but mine.

Uni - verse is kinda telling. i am without reason to invest my identity in cosmology at the present; there's too much "size matters" in the underlying emotional context.

RE: The shape of the universe and what is at it's edge. Turn your noggins on.

The Universe is Flat.
It has zero total energy, came from nothing, and in the end we are all doomed.
Just so you know.
This is one of the best talks on the subject...and his books are excellent also. Any of them.